In connection with the recovery of hydrocarbons from the earth, wellbores are generally drilled using a variety of different methods and equipment. According to one common method, a roller cone bit or fixed cutter bit is rotated against the subsurface formation to form the wellbore. The rotating bit is suspended in the wellbore by a tubular drill string. Drilling fluid is pumped through the drill string and discharged at or near the drill bit. Among other things, the drilling fluid helps to keep the drill bit cool and clean during drilling. In many systems, various wellbore tools (e.g., near-bit reamers and under-reamers) are incorporated in a bottomhole assembly at the lower end of the drill string to facilitate drilling operations. Such tools often require remote activation within the downhole environment of the wellbore.